1. Field of the Invention
This invention relates generally to processing a document or other type of file which contains an encoding containing both indefinite and definite length formats.
The present invention relates more specifically to processing a file which is binary encoded using ASN.1 according to the Standard Page Description Language (SPDL).
2. Discussion of the Background
Processing systems are known in which a data processor can handle input data elements which are fixed or variable in length. For example, U.S. Pat. No. 4,443,860, issued to Vidalin on Apr. 17, 1984, discloses a system for comparison of variable format input data and stored data. However, this reference does not disclose processing of nested definite and indefinite length formats.
The present invention has been developed to process binary encoded standard page description language (SPDL). SPDL is a proposed page description language (PDL) in the process of being developed as an international standard by several people including one of the inventors herein. The proposal is currently in draft form before a section of the International Standards Organization ("ISO") as ISO/IEC DIS 10180 and is available through the American National Standards Institute ("ANSI") in New York.
SPDL is a hierarchically structured page description language which can be encoded in a clear text format or a binary format. The binary encoding of SPDL is performed according to Abstract Syntax Notation 1 ("ASN.1") as defined in ISO/IEC 8824:1990 and uses the Basic Encoding Rules of ASN.1 as defined in ISO/IEC 8825:1990.